the serials on the gun are right as rain for the time of production,also the rivets on the stock are correct.
Which is a good thing, if you want that.
Trouble is, not all the weapons went Factory->Army->Trooper.
Many went Factory->Army->Ordinance Dept->Regiment->Trooper.
Quite a few went Regiment->Trooper->Regiment->Trooper, etc.
Some also went Regiment->Trooper->Trooper->Trooper->Company->Trooper
Some of the DCM-papered Carbines were thoroughly mix-mastered, IBM upper handguards over Rockola stocks with WRA barrels in Standard recievers.
The parts are all out there. Many--the folding stocks--have been out there fifty years. A person, if they found an Inland with intact "L" flip sight, could match parts together to make a weapon that would look just like one that left the Inland Factory in 43', '44 or '45--and none of us would be any the wiser.
Other than the fact that there are now more folding stock Carbines out there than Inland ever made. "Surplus" guys knocked them together by the dozen.
So, a "real" one (meaning with documentation and/or provenance) is as rare as an actual WWII M1C or M1D. Or, put another way, as far too common as 'genuine' Marine M1903A4's or "tanker" Garands.
I'm not trying to wet blanket you--you probably have a real gem, and a man-made diamond is still a diamond (no matter what deBeers would have you believe).
I just don't want you to think you have a $3000 gem when you really have a $990 one. You might very well have a $1050 gem and not $900, too. And, you are still better off than having a $400 Universal dressed up as an $800 cinderella.